Rolling bearing

Abstract

Provided is a rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements. The outer ring includes: a first outer ring raceway member that has a raceway surface on the inner circumference thereof; a first outer ring body that has a contact surface which contacts an outer circumferential surface of the first outer ring raceway member; a second outer ring raceway member that is disposed alongside the first outer ring raceway member in a first axial direction in which a central axis extends, that is fixed with respect to the first outer ring raceway member, and that has a raceway surface on the inner circumference thereof; and a second outer ring body that has a contact surface which contacts an outer circumferential surface of the second outer ring raceway member. The inner ring includes: a first inner ring raceway member that has a raceway surface on the outer circumference thereof; a first inner ring body that has a contact surface which contacts an inner circumferential surface of the first inner ring raceway member; a second inner ring raceway member that is disposed alongside the first inner ring raceway member in the first axial direction in which the central axis extends, that is fixed with respect to the first inner ring raceway member, and that has a raceway surface on the outer circumference thereof; and a second inner ring body that has a contact surface which contacts an inner circumferential surface of the second inner ring raceway member. The first outer ring body, the second outer ring body, the first inner ring body, and the second inner ring body are made of a material that has a lower specific gravity and a higher stiffness than that of the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member, and the second inner ring raceway member.

Description

Rolling bearings

[0001] The present invention relates to a rolling bearing.

[0002] There is known a rolling bearing in which the outer ring and the inner ring each comprise a pair of plate members (see, for example, Patent Document 1). In a rolling bearing in which the outer ring and the inner ring each comprise a pair of plate members, it is known that the plate members constituting the outer ring and the plate members constituting the inner ring are fitted and fixed together, and an adhesive layer is further provided at the fitted portions (see, for example, Patent Document 2).

[0003] JP 2019-178735 A

[0004] There is a need for a rolling bearing that is both lightweight and rigid. Accordingly, one of the objects of the present disclosure is to provide a rolling bearing that is both lightweight and rigid.

[0005] A rolling bearing according to the present disclosure comprises an outer ring, an inner ring having a common central axis with the outer ring and arranged on the inner peripheral side of the outer ring, and a plurality of rolling elements arranged to be able to roll on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. The outer ring includes a first outer ring raceway member having a raceway surface on its inner peripheral, a first outer ring body having an abutment surface that abuts against the outer peripheral surface of the first outer ring raceway member, a second outer ring raceway member arranged alongside the first outer ring raceway member in a first axial direction that is the direction in which the central axis extends and fixed to the first outer ring raceway member, the second outer ring body having a raceway surface on its inner peripheral, and an abutment surface that abuts against the outer peripheral surface of the second outer ring raceway member. The inner ring includes a first inner ring raceway member having a raceway surface on its outer periphery, a first inner ring body having an abutment surface that abuts against the inner periphery of the first inner ring raceway member, a second inner ring raceway member arranged next to the first inner ring raceway member in a first axial direction that is the direction in which the central axis extends and fixed to the first inner ring raceway member, the second inner ring raceway member having a raceway surface on its outer periphery, and a second inner ring body having an abutment surface that abuts against the inner periphery of the second inner ring raceway member. The first outer ring body, the second outer ring body, the first inner ring body, and the second inner ring body are made of a material that has a lower specific gravity and higher rigidity than the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member, and the second inner ring raceway member.

[0006] According to the above rolling bearing, a rolling bearing that is lightweight yet has rigidity is provided.

[0007] FIG. 1 is a perspective view showing the structure of a rolling bearing according to the present disclosure. FIG. 2 is a side view showing the structure of a rolling bearing according to the present disclosure. FIG. 3 is a cross-sectional perspective view showing the structure of a rolling bearing according to the present disclosure. FIG. 4 is a cross-sectional perspective view showing an outer ring and a portion of a rolling element of a rolling bearing according to the present disclosure. FIG. 5 is a perspective view showing a cut-away portion of an outer ring body of a rolling bearing according to the present disclosure. FIG. 6 is a perspective view showing an outer ring raceway member of a rolling bearing according to the present disclosure. FIG. 7 is a cross-sectional perspective view showing an inner ring and a portion of a rolling element of a rolling bearing according to the present disclosure. FIG. 8 is a cut-away perspective view showing an inner ring body of a rolling bearing according to the present disclosure. FIG. 9 is a perspective view showing an inner ring raceway member of a rolling bearing according to the present disclosure. FIG. 10 is a plan view showing the structure of a rolling bearing according to the present disclosure.

[0008] [Summary of the embodiment] First, embodiments of the present disclosure will be described. A rolling bearing according to the present disclosure includes an outer ring, an inner ring having a common central axis with the outer ring and arranged on the inner peripheral side of the outer ring, and a plurality of rolling elements arranged to be able to roll on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. The outer ring includes a first outer ring raceway member having a raceway surface on its inner peripheral, a first outer ring body having an abutment surface that abuts on the outer peripheral surface of the first outer ring raceway member, a second outer ring raceway member arranged alongside the first outer ring raceway member in a first axial direction (the direction in which the central axis extends) and fixed to the first outer ring raceway member, the second outer ring body having a raceway surface on its inner peripheral, and an abutment surface that abuts on the outer peripheral surface of the second outer ring raceway member. The inner ring includes a first inner ring raceway member having a raceway surface on its outer periphery, a first inner ring body having an abutment surface that abuts against the inner periphery of the first inner ring raceway member, a second inner ring raceway member arranged next to the first inner ring raceway member in a first axial direction that is the direction in which the central axis extends and fixed to the first inner ring raceway member, the second inner ring raceway member having a raceway surface on its outer periphery, and a second inner ring body having an abutment surface that abuts against the inner periphery of the second inner ring raceway member. The first outer ring body, the second outer ring body, the first inner ring body, and the second inner ring body are made of a material that has a lower specific gravity and higher rigidity than the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member, and the second inner ring raceway member.

[0009] Conventionally, lightweight rolling bearings are known, for example, from Patent Documents 1 and 2. In the rolling bearings disclosed in these Patent Documents, the outer and inner rings that constitute the rolling bearing are each composed of a pair of axially split members (referred to as a split outer ring and a split inner ring). The split outer ring and the split inner ring are each formed into a predetermined shape by press working or the like, and then fixed to each other by fitting a convex portion formed on one of the pair of split rings into a concave portion formed on the other.

[0010] According to Patent Document 1, a lightweight rolling bearing is realized. However, rolling bearings are required to have rigidity according to the application while maintaining light weight. Under these circumstances, a rolling bearing that is lightweight yet rigid has been studied.

[0011] In the rolling bearing according to the present disclosure, the outer ring and the inner ring are each composed of a member separated in the axial direction. Furthermore, the member having the raceway surface (raceway member) and the main body member disposed outside the raceway surface are composed of separate members made of different materials. The raceway members are fixed to each other and form the raceway for the outer ring and the raceway for the inner ring, respectively. The main body member is composed of a material with a lower specific gravity and higher rigidity than the member having the raceway surface. With these configurations, the use of a lightweight, highly rigid material for the main body member makes the entire bearing lightweight and rigid, while a material suitable for ensuring bearing functionality can be selected for the material of the raceway surface. These configurations make it possible to provide a lightweight and rigid bearing.

[0012] In the above-described rolling bearing, the first outer ring raceway member may have a plurality of first outer ring fixing portions spaced apart from one another in the circumferential direction, and the second outer ring raceway member may have a plurality of second outer ring fixing portions spaced apart from one another in the circumferential direction, such that the first outer ring fixing portions and the second outer ring fixing portions are fitted together to secure the first outer ring raceway member and the second outer ring raceway member to one another. The first inner ring raceway member may have a plurality of first inner ring fixing portions spaced apart from one another in the circumferential direction, and the second inner ring raceway member may have a plurality of second inner ring fixing portions spaced apart from one another in the circumferential direction, such that the first inner ring fixing portions and the second inner ring fixing portions are fitted together to secure the first inner ring raceway member and the second inner ring raceway member to one another. With these configurations, the outer ring raceway members and the inner ring raceway members are securely fixed to one another, and in addition to being fixed radially, misalignment in the circumferential direction is particularly suppressed. This more reliably achieves the effects of the present disclosure.

[0013] In the above-described rolling bearing, the first outer ring body and the second outer ring body may be disposed spaced apart from each other in the first axial direction, with the first outer ring raceway member and the second outer ring raceway member sandwiched between them. The first inner ring body and the second inner ring body may be disposed spaced apart from each other in the first axial direction, with the first inner ring raceway member and the second inner ring raceway member sandwiched between them. These configurations allow the first outer ring body and the second outer ring body (the first inner ring body and the second inner ring body) to be components of the same shape. Furthermore, the first outer ring body and the second outer ring body (the first inner ring body and the second inner ring body) can also be components of different shapes, allowing for a high degree of design freedom depending on the application and location of application.

[0014] In the above-described rolling bearing, the first outer ring raceway member and the second outer ring raceway member may each have, on their outer peripheries, an outer peripheral plane extending perpendicular to the first axial direction and an outer peripheral wall surface extending along the first axial direction, and the first outer ring body and the first outer ring raceway member, and the second outer ring body and the second outer ring raceway member, respectively, may abut against each other at the outer peripheral plane and the outer peripheral wall surface. The first inner ring raceway member and the second inner ring raceway member may each have, on their inner peripheries, an inner peripheral plane extending perpendicular to the first axial direction and an inner peripheral wall surface extending along the first axial direction, and the first inner ring body and the first inner ring raceway member, and the second inner ring body and the second inner ring raceway member, respectively, may abut against each other at the inner peripheral plane and the inner peripheral wall surface. With these configurations, a rolling bearing having rigidity can be obtained even when the outer ring raceway member and the inner ring raceway member are made of a relatively thin material such as a plate or sheet material.

[0015] In the above-described rolling bearing, the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member, and the second inner ring raceway member may be made of steel, and the first outer ring body, the second outer ring body, the first inner ring body, and the second inner ring body may be made of ceramics. With this configuration, known manufacturing methods can be applied to the components having raceway surfaces (the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member, and the second inner ring raceway member), ensuring the precision and durability required of a bearing. At the same time, by using ceramics, a material that combines light weight and rigidity, for the main body, a bearing that combines light weight and rigidity can be reliably obtained.

[0016] In the above-mentioned rolling bearing, when the rolling bearing is viewed in a plane in the first axial direction, the outer contour of the outer ring may include a portion that is recessed radially inward relative to an imaginary outer contour circle that is centered on the central axis and passes through the portion of the outer contour of the outer ring farthest from the central axis. The inner contour of the inner ring may include a portion that is recessed radially outward relative to an imaginary inner contour circle that is centered on the central axis and passes through the portion of the inner contour of the inner ring closest to the central axis. With this configuration, part of the outer peripheral side and part of the inner peripheral side of the bearing are removed as so-called lightening portions, making it possible to achieve further weight reduction.

[0017] [Specific Example of Embodiment] Next, an example of a specific embodiment of the rolling bearing of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and their description will not be repeated. In the following description, the direction along the axis of the rolling bearing may be referred to as the thickness direction of the rolling bearing. Furthermore, the direction perpendicular to the axis of the rolling bearing may be referred to as the surface direction of the rolling bearing.

[0018] Fig. 1 is a perspective view showing the structure of a rolling bearing according to an embodiment of the present disclosure. Referring to Fig. 1, the rolling bearing 1 includes an outer ring 10, an inner ring 50, and rollers 40 as rolling elements. The outer ring 10 and the inner ring 50 share a common central axis R. The inner ring 50 is disposed on the inner peripheral side of the outer ring 10. The rolling bearing 1 has a plane-symmetrical shape with respect to a plane (referred to as the central plane) that passes through the center in the thickness direction and is perpendicular to the central axis R. In other words, the rolling bearing 1 has no distinguishable front or back.

[0019] Fig. 2 is a side view of the rolling bearing 1 as viewed from a direction perpendicular to the central axis R. Referring to Fig. 2, the outer ring 10 includes a pair of members, a first outer ring body 20A and a second outer ring body 20B, and a pair of members, a first outer ring raceway member 30A and a second outer ring raceway member 30B. The first outer ring body 20A and the second outer ring body 20B are members of the same shape. The first outer ring raceway member 30A and the second outer ring raceway member 30B are members of the same shape. The second outer ring raceway member 30B is arranged alongside the first outer ring raceway member 30A in the direction in which the central axis R extends. The first outer ring body 20A and the second outer ring body 20B are spaced apart from each other, with the outer ring raceway members 30A, 30B sandwiched between them. The first outer ring body 20A, the first outer ring raceway member 30A, the second outer ring raceway member 30B, and the second outer ring body 20B are in close contact with each other in the thickness direction in this order.

[0020] 1 and 2, the rolling bearing 1 has a first main surface 1a and a second main surface 1b, which are both flat end surfaces in the direction along the central axis R. By configuring the first main surface 1a and the second main surface 1b to be flat, a large contact area with the mating member can be ensured, and stable operation of the bearing can be ensured.

[0021] FIG. 3 is a cross-sectional perspective view showing an enlarged portion of the rolling bearing 1, illustrating the cross-sectional structure. Referring to FIG. 3, the inner ring 50 includes a pair of members, a first inner ring body 60A and a second inner ring body 60B, and a pair of members, a first inner ring raceway member 70A and a second inner ring raceway member 70B. The first inner ring body 60A and the second inner ring body 60B are members of the same shape. The first inner ring raceway member 70A and the second inner ring raceway member 70B are members of the same shape. The second inner ring raceway member 70B is arranged next to the first inner ring raceway member 70A in the direction in which the central axis R extends (see FIG. 1). The first inner ring body 60A and the second inner ring body 60B are spaced apart from each other, with the inner ring raceway members 70A, 70B sandwiched between them. The first inner ring body 60A, the first inner ring raceway member 70A, the second inner ring raceway member 70B, and the second inner ring body 60B are in close contact with each other in the thickness direction in this order.

[0022] The members constituting the raceway surfaces of the rolling bearing 1, i.e., the first outer ring raceway member 30A, the second outer ring raceway member 30B, the first inner ring raceway member 70A, and the second inner ring raceway member 70B, are each made of steel, for example. The outer ring raceway members 30A, 30B and the inner ring raceway members 70A, 70B are made of steel plate processed into a predetermined shape. The steel material may be, for example, SCM415 as specified in the JIS standard. The thickness of the steel plate may be, for example, approximately 0.4 mm to 3.2 mm.

[0023] The members constituting the main body of the rolling bearing 1, i.e., the first outer ring body 20A, the second outer ring body 20B, the first inner ring body 60A, and the second inner ring body 60B, are each made of a material with a lower specific gravity and higher rigidity than the outer ring raceway members 30A, 30B and the inner ring raceway members 70A, 70B. The materials for the outer ring bodies 20A, 20B and the inner ring bodies 60A, 60B may be, for example, ceramics, aluminum, engineering plastic resin, magnesium, or a composite of metal and ceramics (for example, an aluminum / SiC composite material in which SiC ceramic particles are contained in an aluminum alloy). The outer ring bodies 20A, 20B and the inner ring bodies 60A, 60B may preferably be, for example, ceramics. The ceramic material may be, for example, silicon carbide (SiC), silicon nitride (Si ３ N ４ ), alumina (Al ２ O ３ ), and may contain two or more of these.

[0024] 1 and 3 , the outer ring raceway members 30A and 30B each include a first portion 35A, 35B, a second portion 36A, 36B, and a third portion 37A, 37B. The first portion 35A, 35B, the second portion 36A, 36B, and the third portion 37A, 37B may have substantially the same thickness. The first portion 35A, 35B is a portion having an annular disk shape. The first portion 35A, 35B has a common central axis with the central axis R of the rolling bearing 1. The second portion 36A, 36B has a cylindrical shape. The outer shape of the second portion 36A, 36B is a truncated cone. The second portion 36A, 36B extends from the inner edge of the first portion 35A, 35B in the thickness direction such that the inner diameter decreases with increasing distance from the first portion 35A, 35B. The second portions 36A, 36B have annular inner circumferential surfaces 39a, 39b. The inner circumferential surfaces 39a, 39b share a central axis with the central axis R of the rolling bearing 1. Rollers 40 roll on the inner circumferential surfaces 39a, 39b. In other words, the inner circumferential surfaces 39a, 39b are raceway surfaces. The third portions 37A, 37B have a cylindrical shape. The third portions 37A, 37B share a central axis with the central axis R of the rolling bearing 1. The third portions 37A, 37B are connected to the ends of the second portions 36A, 36B on the opposite side in the thickness direction (central axis direction) from the first portions 35A, 35B, and extend along the central axis.

[0025] 1 and 3, the inner ring raceway members 70A and 70B each include a first portion 75A and 75B, a second portion 76A and 76B, and a third portion 77A and 77B. The first portions 75A and 75B, the second portions 76A and 76B, and the third portions 77A and 77B may have substantially the same thickness. Furthermore, it is preferable that the first portions 75A and 75B have substantially the same thickness as the first portions 35A and 35B of the outer ring raceway members 30A and 30B. The first portions 75A and 75B have an annular disk shape. The first portions 75A and 75B share a central axis with the central axis R of the rolling bearing 1. The second portions 76A and 76B have a cylindrical shape. The outer shape of the second portions 76A and 76B is a truncated cone. The second portions 76A, 76B extend from the outer edges of the first portions 75A, 75B in the thickness direction so that their outer diameters increase with increasing distance from the first portions 75A, 75B. The second portions 76A, 76B have annular outer peripheral surfaces 79a, 79b ( FIG. 7 ). The outer peripheral surfaces 79a, 79b share a central axis with the central axis R of the rolling bearing 1. The rollers 40 roll on the outer peripheral surfaces 79a, 79b. In other words, the outer peripheral surfaces 79a, 79b are raceway surfaces. The third portions 77A, 77B have a cylindrical shape. The third portions 77A, 77B share a central axis with the central axis R of the rolling bearing 1. The third portions 77A, 77B are connected to the ends of the second portions 76A, 76B on the opposite side in the thickness direction (central axis direction) from the first portions 75A, 75B, and extend along the central axis. The third portions 37A, 37B of the outer ring raceway members 30A, 30B face the third portions 77A, 77B of the inner ring raceway members 70A, 70B, respectively, with a gap between them.

[0026] FIG. 4 is a cross-sectional perspective view showing a portion of the outer ring 10 and rollers 40 of the rolling bearing 1. Referring to FIG. 4, the rollers 40 include a plurality of first rollers 41 and a plurality of second rollers 42. The first rollers 41 and the second rollers 42 are made of, for example, steel. More specifically, they may be made of, for example, SUJ2 as specified in the JIS standard. The first rollers 41 and the second rollers 42 are cylindrical. Each of the first rollers 41 and the second rollers 42 has a cylindrical outer peripheral surface and circular end faces at both ends of the outer peripheral surface. The first rollers 41 and the second rollers 42 are arranged alternately in the circumferential direction. The first rollers 41 roll on the inner peripheral surface 39a of the first outer ring raceway member 30A. The second rollers 42 roll on the inner peripheral surface 39b of the second outer ring raceway member 30B. The inner peripheral surfaces 39a and 39b are outer wall surfaces that define the raceway 11 of the rolling bearing 1.

[0027] The first outer ring body 20A has an abutment surface that abuts against the outer peripheral surface of the first outer ring raceway member 30A. The second outer ring body 20B has an abutment surface that abuts against the outer peripheral surface of the second outer ring raceway member 30B. The arrangement of the outer ring raceway members and the outer ring bodies will be described in more detail. The first portions 35A and 35B of the outer ring raceway members 30A and 30B have outer peripheral flat surfaces 351a and 351b that extend perpendicular to the direction of the central axis R (see FIG. 2). The outer ring bodies 20A and 20B each have surfaces 251a and 251b that abut against the outer peripheral flat surfaces 351a and 351b. The third portions 37A and 37B of the outer ring raceway members 30A and 30B have outer peripheral wall surfaces 371a and 371b that extend along the direction of the central axis R (see FIG. 2). The outer ring bodies 20A, 20B have surfaces 271a, 271b that abut against the outer peripheral wall surfaces 371a, 371b, respectively. That is, the outer ring bodies 20A, 20B abut against the outer ring raceway members 30A, 30B on the surfaces of the outer peripheral surfaces of the outer ring raceway members 30A, 30B that are perpendicular to and parallel to the central axis R.

[0028] The second portions 36A, 36B of the outer ring raceway members 30A, 30B do not abut against the outer ring bodies 20A, 20B. However, as a modified example, the second portions 36A, 36B of the outer ring raceway members 30A, 30B may abut against the outer ring bodies 20A, 20B.

[0029] The outer ring 10 is provided with eight mounting portions 13 spaced equally apart around the periphery. By inserting a screw or the like into the mounting portions 13 and tightening them, the four members constituting the outer ring 10, i.e., the outer ring bodies 20A, 20B and the outer ring raceway members 30A, 30B, can be fastened together and fixed, and the rolling bearing 1 can be fixed to the mounting partner, which is an external member.

[0030] FIG. 5 is a perspective view showing the first outer ring body 20A. The first outer ring body 20A is cut away. The first outer ring body 20A includes an annular portion 25A and eight protruding portions 21A that protrude radially outward from the annular portion 25A. The annular portion 25A has contact surfaces 271a, 251a that contact the first outer ring raceway member 30A (FIG. 4). The protruding portions 21A form the mounting portion 13. A hole 22A is formed in the protruding portion 21A that penetrates in the central axis direction. The hole 22A functions as a mounting hole. The second outer ring body 20B has the same shape as the first outer ring body 20A, and a description thereof will be omitted. The first outer ring body 20A is made of, for example, ceramics.

[0031] FIG. 6 is a perspective view showing the first outer ring raceway member 30A. Referring to FIGS. 4 and 6, the first outer ring raceway member 30A has a first portion 35A, a second portion 36A, and a third portion 37A. Eight protrusions 31A are provided, protruding radially outward from the first portion 35A, which is a circular disk-shaped portion. The protrusions 31A constitute the mounting portion 13. A hole 32A is formed in the protrusion 31A, penetrating it in the central axis direction. The shape of the protrusion 31A is substantially the same as that of the protrusion 21A (FIG. 5). The diameter of the hole 32A is the same as that of the hole 22A (FIG. 5). The hole 32A functions as a mounting hole. The second outer ring raceway member 30B has the same shape as the first outer ring raceway member 30A, and therefore a description thereof will be omitted.

[0032] When the first outer ring raceway member 30A and the first outer ring main body 20A are combined, and further when the first outer ring raceway member 30A, the second outer ring raceway member 30B, the first outer ring main body 20A, and the second outer ring main body 20B are combined, the protrusions of each member are positioned at the same location in the circumferential direction, allowing the members to be fastened and fixed together. They can also be attached to a mating member. The number of protrusions provided on the outer ring main body and the outer ring raceway member can be an appropriate number depending on the overall dimensions of the rolling bearing, etc. The number of protrusions may be, for example, 6 to 12.

[0033] Eight outer ring fixing portions 33A are provided, separate from the protruding portions 31A, protruding radially outward from the first portion 35A of the first outer ring raceway member 30A. The eight outer ring fixing portions 33A are provided at equal intervals in the circumferential direction. The outer ring fixing portions 33A and the protruding portions 31A are arranged so as to alternate. Either a convex portion 34A or a concave portion 38A is formed on the outer ring fixing portion 33A. The convex portions 34A and the concave portions 38A are arranged alternately in the circumferential direction. The convex portion 34A is a portion that protrudes in the opposite direction to the extension direction of the third portion 37A. The convex portion 34A is a cylindrical protrusion. The concave portion 38A is a hole with substantially the same diameter as the cylindrical protrusion of the convex portion 34A. The second outer ring raceway member 30B has a similar structure. With these structures, the recessed or protruding portions provided on the second outer ring raceway member 30B are combined with the protruding portions 34A or recessed portions 38A, and the first outer ring raceway member 30A and the second outer ring raceway member 30B are fitted and fixed to each other. The number of outer ring fixing portions can be set appropriately depending on the overall dimensions of the rolling bearing, etc. The number of protruding portions may be, for example, 6 to 12.

[0034] Figure 7 is a cross-sectional perspective view showing a portion of the inner ring 50 and roller 40 of the rolling bearing 1. Referring to Figure 7, the second roller 42 rolls on the outer peripheral surface 79b of the second inner ring raceway member 70B. The first roller (see Figure 4) rolls on the outer peripheral surface 79a of the first inner ring raceway member 70A. The outer peripheral surfaces 79a, 79b are inner wall surfaces that define the raceway 11 of the rolling bearing 1.

[0035] The first inner ring body 60A has an abutment surface that abuts against the inner circumferential surface of the first inner ring raceway member 70A. The second inner ring body 60B has an abutment surface that abuts against the inner circumferential surface of the second inner ring raceway member 70B. The arrangement of the inner ring raceway members and the inner ring bodies will be described in more detail. The first portions 75A and 75B of the inner ring raceway members 70A and 70B have inner circumferential flat surfaces 751a and 751b that extend perpendicular to the direction of the central axis R (see FIG. 2). The inner ring bodies 60A and 60B each have surfaces 651a and 651b that abut against the inner circumferential flat surfaces 751a and 751b. The third portions 77A and 77B of the inner ring raceway members 70A and 70B have inner circumferential wall surfaces 771a and 771b that extend along the direction of the central axis R (see FIG. 2). The inner ring bodies 60A, 60B have surfaces 671a, 671b that abut against the inner peripheral wall surfaces 771a, 771b, respectively. That is, the inner ring bodies 60A, 60B abut against the inner ring raceway members 70A, 70B on the inner peripheral surfaces of the inner ring raceway members 70A, 70B that are perpendicular to and parallel to the central axis R.

[0036] The second portions 76A, 76B of the inner ring raceway members 70A, 70B do not abut against the inner ring bodies 60A, 60B. However, as a modified example, the second portions 76A, 76B may abut against the inner ring bodies 60A, 60B.

[0037] The inner ring 50 is provided with six mounting portions 16 spaced equally apart around the periphery. By inserting a screw or the like into the mounting portions 16 and tightening them, the four members constituting the inner ring 50, i.e., the inner ring bodies 60A, 60B and the inner ring raceway members 70A, 70B, can be fastened together and fixed, and the rolling bearing 1 can be fixed to the mounting partner, which is an external member.

[0038] FIG. 8 is a perspective view showing the first inner ring body 60A. The first inner ring body 60A is cut away. The first inner ring body 60A includes an annular portion 65A and six protruding portions 61A that protrude radially inward from the annular portion 65A. The annular portion 65A has contact surfaces 671a, 651a that contact the first inner ring raceway member 70A ( FIG. 7 ). The protruding portions 61A form the mounting portion 16. A hole 62A that penetrates the protruding portion 61A in the central axis direction is formed in the protruding portion 61A. The hole 62A is a mounting hole. The second inner ring body 60B has the same shape as the first inner ring body 60A, and a description thereof will be omitted. The first inner ring body 60A is made of, for example, ceramics.

[0039] FIG. 9 is a perspective view of the first inner ring raceway member 70A. Referring to FIGS. 4 and 9, the first inner ring raceway member 70A has a first portion 75A, a second portion 76A, and a third portion 77A. Six protrusions 71A are provided, protruding radially inward from the first portion 75A, which is a circular disk-shaped portion. The protrusions 71A constitute the mounting portion 16. A hole 72A is formed in the protrusion 71A, penetrating it in the central axis direction. The shape of the protrusion 71A is substantially the same as that of the protrusion 61A (FIG. 8). The diameter of the hole 72A is the same as that of the hole 62A (FIG. 8). The second inner ring raceway member 70B has the same shape as the first inner ring raceway member 70A, and therefore a description thereof will be omitted.

[0040] When the first inner ring raceway member 70A and the first inner ring main body 60A are combined, and further when the first inner ring raceway member 70A, the second inner ring raceway member 70B, the first inner ring main body 60A, and the second inner ring main body 60B are combined, the protrusions of each member are positioned at the same location in the circumferential direction, allowing the members to be fastened and fixed together. The number of protrusions provided on the inner ring main body and the inner ring raceway member can be an appropriate number depending on the overall dimensions of the rolling bearing, etc. The number of protrusions may be, for example, four to eight.

[0041] Six inner ring fixing portions 73A are provided, separate from the protruding portions 71A, protruding radially inward from the first portion 75A of the first inner ring raceway member 70A. The six inner ring fixing portions 73A are provided at equal intervals in the circumferential direction. The inner ring fixing portions 73A and the protruding portions 71A are arranged so as to alternate. Either a protruding portion 74A or a recessed portion 38A is formed on the inner ring fixing portion 73A. The protruding portions 74A and the recessed portions 78A are arranged alternately in the circumferential direction. The protruding portion 74A protrudes in the direction opposite to the extension direction of the third portion 77A, in the central axis direction (i.e., in the direction in which the second inner ring raceway member 70B is located). The protruding portion 74A is a cylindrical protrusion. The recessed portion 78A is a hole having substantially the same diameter as the protruding portion 74A. The second inner ring raceway member 70B has a similar structure, and the first inner ring raceway member 70A and the second inner ring raceway member 70B are fitted and fixed to each other by combining the recessed or protruding portions provided on the second inner ring raceway member 70B with the protruding portion 74A or the recessed portion 78A. The number of inner ring fixing portions can be set appropriately depending on the overall dimensions of the rolling bearing, etc. The number of protruding portions may be, for example, four to eight.

[0042] FIG. 10 is a plan view showing the structure of the rolling bearing 1. FIG. 10 shows the rolling bearing 1 as viewed in a plane in the direction of the central axis R. Referring to FIG. 10, the outer contour of the outer ring 10 has a portion recessed radially inward from an imaginary outer contour circle C1 that surrounds the outermost periphery of the rolling bearing 1. The recessed portion is a so-called hollowed-out portion. The imaginary outer contour circle C1 is an imaginary circle of radius r1 that passes through the portion of the outer contour of the outer ring 10 that is farthest from the central axis R. The radius r2, which is the radius of the annular portion 25A of the outer ring 10, may be approximately 40 to 85% of radius r1. Hollowing out a portion of the outer periphery enables further weight reduction. The specific values ​​of radii r1 and r2 are not limited, but for example, radius r1 may be 40 to 150 mm, and radius r2 may be 32 to 138 mm.

[0043] The inner contour of the inner ring 50 has a portion recessed radially outward from an imaginary outer contour circle C2 that surrounds the innermost circumference of the rolling bearing 1. The recessed portion is a so-called hollowed-out portion. The imaginary outer contour circle C2 is an imaginary circle of radius r3 that passes through the portion of the inner contour of the inner ring 50 that is closest to the central axis R. The radius r3 may be approximately 40 to 85% of the radius r4, which is the radius of the annular portion 65A of the inner ring 50. Hollowing out a portion of the inner circumference can further reduce the weight. The specific values ​​of radii r3 and r4 are not limited, but for example, the radius r3 may be 1.5 to 100 mm, and the radius r4 may be 9.5 to 112 mm.

[0044] The axial thickness of the rolling bearing according to the present disclosure is not particularly limited, but may be, for example, 4 to 20 mm.

[0045] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present invention is defined not by the above description but by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0046] 1 Rolling bearing, 10 Outer ring, 11 Raceway, 13, 16 Mounting portion, 20A, 20B Outer ring body, 30A, 30B Outer ring raceway member, 21A, 31A Protrusion, 22A, 32A Hole, 25A Annular portion, 33A Outer ring fixing portion, 34A Convex portion, 38A Concave portion, 40, 41, 42 Roller, 50 Inner ring, 60A, 60B Inner ring body, 70A, 70B Inner ring raceway member, 61A, 71A Protrusion, 62A, 72A Hole, 65A Annular portion, 73A Inner ring fixing portion, 74A Convex portion, 78A Concave portion.

Claims

1. A bearing comprising: an outer ring; an inner ring having a common central axis with said outer ring and arranged on the inner peripheral side of said outer ring; and a plurality of rolling elements arranged to be able to roll on the inner peripheral surface of said outer ring and the outer peripheral surface of said inner ring, wherein said outer ring comprises: a first outer ring raceway member having a raceway surface on its inner peripheral; a first outer ring body having an abutment surface abutting the outer peripheral surface of said first outer ring raceway member; a second outer ring raceway member having a raceway surface on its inner peripheral, arranged alongside said first outer ring raceway member in a first axial direction which is the direction in which said central axis extends and fixed to said first outer ring raceway member; and a second outer ring body having an abutment surface abutting the outer peripheral surface of said second outer ring raceway member, wherein said inner ring comprises: a first inner ring raceway member having a raceway surface on its outer peripheral; and a first inner ring body having an abutment surface abutting the inner peripheral surface of said first inner ring raceway member, a second inner ring raceway member having a raceway surface on its outer periphery, the second inner ring raceway member being arranged alongside the first inner ring raceway member in a first axial direction, which is the direction in which the central axis extends, and being fixed to the first inner ring raceway member; and a second inner ring body having an abutment surface that abuts the inner periphery of the second inner ring raceway member, wherein the first outer ring body, the second outer ring body, the first inner ring body, and the second inner ring body are made of a material that has a lower specific gravity and higher rigidity than the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member, and the second inner ring raceway member.

2. A rolling bearing as claimed in claim 1, wherein the first outer ring raceway member has a plurality of first outer ring fixing portions arranged at a distance from one another in the circumferential direction, the second outer ring raceway member has a plurality of second outer ring fixing portions arranged at a distance from one another in the circumferential direction, the first outer ring fixing portions and the second outer ring fixing portions being fitted together, thereby fixing the first outer ring raceway member and the second outer ring raceway member to each other, the first inner ring raceway member has a plurality of first inner ring fixing portions arranged at a distance from one another in the circumferential direction, the second inner ring raceway member has a plurality of second inner ring fixing portions arranged at a distance from one another in the circumferential direction, and the first inner ring raceway member and the second inner ring raceway member being fixed to each other by fitting together the first inner ring fixing portions and the second inner ring fixing portions.

3. A rolling bearing as described in claim 1 or claim 2, wherein the first outer ring body and the second outer ring body are arranged spaced apart from each other in the first axial direction, sandwiching the first outer ring raceway member and the second outer ring raceway member, and the first inner ring body and the second inner ring body are arranged spaced apart from each other in the first axial direction, sandwiching the first inner ring raceway member and the second inner ring raceway member.

4. A rolling bearing as set forth in claim 1 or claim 2, wherein each of the first outer ring raceway member and the second outer ring raceway member has, on its outer periphery, an outer peripheral plane extending perpendicular to the first axial direction and an outer peripheral wall surface extending along the first axial direction, the first outer ring body and the first outer ring raceway member, and the second outer ring body and the second outer ring raceway member abut against each other at the outer peripheral plane and the outer peripheral wall surface, respectively; each of the first inner ring raceway member and the second inner ring raceway member has, on its inner periphery, an inner peripheral plane extending perpendicular to the first axial direction and an inner peripheral wall surface extending along the first axial direction, and the first inner ring body and the first inner ring raceway member, and the second inner ring body and the second inner ring raceway member abut against each other at the inner peripheral plane and the inner peripheral wall surface, respectively.

5. A rolling bearing as set forth in claim 1 or claim 2, wherein the first outer ring raceway member, the second outer ring raceway member, the first inner ring raceway member and the second inner ring raceway member are made of steel, and the first outer ring body, the second outer ring body, the first inner ring body and the second inner ring body are made of ceramics.

6. A rolling bearing according to claim 1 or claim 2, wherein, when the rolling bearing is viewed in a plane in the first axial direction, the outer contour of the outer ring includes a portion that is recessed radially inward relative to an imaginary outer contour circle that is centered on the central axis and passes through the portion of the outer contour of the outer ring farthest from the central axis, and the inner contour of the inner ring includes a portion that is recessed radially outward relative to an imaginary inner contour circle that is centered on the central axis and passes through the portion of the inner contour of the inner ring nearest to the central axis.

Images